United States Central Command forces initiated a sweeping blockade of all maritime traffic entering and exiting Iranian ports on Monday at 10 am ET (7:30 pm IST, enforcing President Donald Trump's proclamation amid escalating conflict in the Middle East.

The operation targets vessels of all nations heading to or from Iranian ports along the Arabian Gulf and Gulf of Oman, but CENTCOM emphasized it will spare ships transiting the Strait of Hormuz to non-Iranian destinations.

"CENTCOM forces will not impede freedom of navigation for vessels transiting the Strait of Hormuz to and from non-Iranian ports," the command stated in an official release.

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Commercial mariners received advance warnings through formal notices, with instructions to monitor Notice to Mariners broadcasts and contact US naval forces on bridge-to-bridge channel 16 in the Gulf of Oman and Strait approaches.

The move risks disrupting global oil flows, as the Strait handles about 20% of the world's crude.

NATO Backs US-Led Action

Hours after Trump claimed international support for the blockade, a senior NATO military official revealed a counter-effort. Speaking to American news outlet CBS News, the official said: "The UK is leading planning efforts of a coalition comprised of more than 40 nations from around the world, many of which are from NATO, to reopen the Strait of Hormuz and protect freedom of navigation."

Details remain vague, but the official added: "They are discussing what to do and when to do it, including the pre-positioning of assets now."

Trump, who has repeatedly lambasted NATO during the ongoing war, expressed frustration Sunday night. "I'm very disappointed in NATO, they weren't there for us. We pay trillions of dollars for NATO, and they weren't there for us," he told reporters.

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However, a UK government spokesperson reinforced his country's stance: "We continue to support freedom of navigation and the opening of the Strait of Hormuz, which is urgently needed to support the global economy and the cost of living back home. The Strait of Hormuz must not be subject to tolling. We are urgently working with France and other partners to put together a wide coalition to protect freedom of navigation."

In a Truth Social post Sunday, Trump insisted other nations would participate without naming them. He later told Fox News: "The UK and a couple of other countries are sending mine sweepers."

The blockade marks a sharp escalation, potentially stranding Iranian oil exports and spiking energy prices worldwide. Analysts warn of retaliatory actions from Tehran, including mine-laying or asymmetric attacks, while the emerging NATO-led coalition signals deepening allied divisions over US strategy.

Markets reacted swiftly, with Brent crude futures jumping 5% in early trading. Shipping firms rerouted vessels, and insurers hiked premiums for Gulf transits